Conveyor Ware Washer

ABSTRACT

Conveyor ware washer, comprising of a treatment device ( 70 ) for the treatment of sprayed final rinse liquid and/or post wash liquid, resp., so that the treated final rinse liquid and post wash liquid, resp. has the quality of potable water from the microbiological perspective and can be reused as final rinse liquid.

The invention concerns a conveyor ware washer, particularly a commercialconveyor ware washer of the type commonly configured in the form of aflight-type ware washer or in the form of a rack conveyor ware washer.

Conveyor ware washers are known for e.g. from the U.S. Pat. No.3,789,860, U.S. Pat. No. 4,231,806, DE 196 44 438 C2 and DE 198 29 650C2.

Two factors largely contribute toward the total consumption of water incase of conveyor ware washers. These factors are the initial filling ofthe conveyor ware washer with fresh water in all tanks and the use offresh water for the final rinse while the conveyor ware washer isoperating. The final rinse liquid used for the final rinse must be of“potable water quality” in microbiological terms. In the state of theart, this potable water is taken from the building water supply and iscompletely consumed.

It would be desirable to provide a conveyor ware washer with reducedconsumption of fresh water. This aim is achieved by a conveyorwarewasher with the features of claim 1 and/or claim 2.

A considerable amount of fresh water will be saved with this invention.

Sprayed final rinse liquid or post-wash liquid is treated in such amanner that it either has the quality of potable water from amicrobiological perspective or that it can be mixed in such a proportionwith water taken from the building water supply that the resulting watermixture has the quality of potable water in microbiological terms. Thetreatment of the sprayed final rinse liquid or the post-wash liquid maybe done with the help of a micro-filtration system or anultra-filtration system. Hygiene may guaranteed by the addition of ozoneas a disinfecting agent, in case this is necessary in addition to thefiltration.

The major difference between micro-filtration and ultra-filtration liesin the different pore sizes and different structures of themicro-filtration and ultra-filtration elements, which are preferablymembranes. If they have a pore size of less than 0.1 μm, the filtrationis designated as ultra-filtration, whereas filtration with a pore sizeof more than 0.1 μm to 100 μm is designated as micro-filtration.

An embodiment of the invention is described below with reference to theattached drawings on the basis of examples. The drawings show:

FIG. 1 diagrammatic lateral view of a section from a conveyor warewasher,

FIG. 2 a second embodiment in lateral view,

FIG. 3 a third embodiment in lateral view,

FIG. 4 a fourth embodiment in lateral view,

FIG. 5 a first embodiment of an ozone adding device,

FIG. 6 another embodiment of an ozone adding device,

FIG. 7 one more embodiment of an ozone adding device.

A treatment device as per the invention can either be integrated in theconveyor ware washer or connected to the conveyor ware washer or belocated separately.

By way of example, the conveyor ware washers as per the invention givenin the drawings can either be rack conveyor ware washers or flight-typeware washers.

According to the drawings, the conveyor ware washers contain at leastone wash zone, from which for example two wash zones 3 and 5 arerepresented, and at least one final rinse zone 25 which, in wash waretransport direction 42, is arranged after the wash zones. The wash zones3 and 5 each contain a wash system with for example upper wash nozzles 6and 8 and lower wash nozzles 10 and 12. A wash tank 14 and 16 isprovided for each wash zone 3 and 5 for the collection of wash liquidsprayed in wash zone 3 and 5. The wash liquid sprayed by the washnozzles 6, 10 and 8, 12 resp. of each wash zone 3 and 5 resp. isrecirculated by means of a pump 18 and 20 resp. from the respective washtank 14 and 16 resp. through a wash liquid-supply pipe 19 and 21 resp.again to the wash nozzles 6, 10 and 8, 12.

The final rinse zone 25 contains, for example, the upper final rinsenozzles 24 and lower final rinse nozzles 26. Fresh final rinse liquidcan be supplied through a final rinse liquid supply device 28 to thefinal rinse nozzles 24 and 26. The final rinse liquid supply device 28can contain a water heater 30, preferably a boiler, a pump 32 and afinal rinse liquid supply pipe 27 connecting the pump 32 with the finalrinse nozzles 24, 26, and can be connected to a fresh water supply pipe34.

A transport device 40 conveys the wash ware to be cleaned in transportdirection 42, which is shown by an arrow, through the wash zones 3 and 5and then through the final rinse zone 25.

A dry zone 44 can be provided in the transport direction 42 after thefinal rinse zone 25, through which the wash ware is transported from thetransport device 40. The dry zone 44 is schematically described in FIGS.1 and 2.

The FIGS. 1, 2 and 3 show an embodiment, for which a post-wash zone 46is located between the last wash zone 5 and the final rinse zone 25. Fore.g. upper post-wash nozzles 50 and lower post-wash nozzles 52 are foundin the post-wash zone 46, to which sprayed final rinse liquid issupplied as post-wash liquid from a post-wash tank 54 through apost-wash liquid-supply pipe 56 with the help of a pump 58. The sprayedfinal rinse liquid in the final rinse zone 25 from the final rinsenozzles 24 and 26, and at least a part of the sprayed post-wash liquidin the post-wash zone 46 from the post wash nozzles 50 and 52 collect inthe post-wash tank 54. Another part of the post-wash liquid sprayed fromthe post wash nozzles 50 and 52 is preferably collected through aconduction element 60 and led into the wash tank 16 of the last washzone 5.

The post-wash liquid sprayed by the post-wash nozzles 50, 52 in thepost-wash zone 46 is therefore re-used final rinse liquid sprayed oncein the final rinse zone 25 by the final rinse nozzles 24 and 26.Therefore, the post-wash zone 46 can also be designated as pre-rinsezone 46, the post-wash nozzles 50, 52 can also be designated aspre-rinse nozzles 50, 52 and post-wash liquid can also be designated aspre-rinse liquid.

The final rinse liquid is water which possesses the quality of potablewater from the microbiological perspective, with or without an additionof rinse aid.

In FIGS. 1, 2 and 3 the post-wash tank 54 and the wash-tanks 16 and 14are connected to a liquid-overflow-cascade system, in which the liquidcan flow opposite to the transport direction 42 of the transport device40 from the post-wash tank 54 into the last wash tank 16 and from hereto the preceding wash tank 14 etc.

The wash liquid is water, to which the detergent is added.

FIG. 4 is identical to the embodiments as per FIGS. 1, 2 and 3 with theexception that no post-wash zone 46 is provided. Accordingly, FIG. 4also has no post-wash tank 54, but a floor 62 or floor trough 64 isprovided for collection of the final rinse liquid which is sprayed fromthe final rinse spray nozzles 24 and 26 in the final rinse zone 25, fromwhich the sprayed final rinse liquid can flow into the neighbouring lastwash tank 16.

The first wash tank 14 in the transport direction 42, which is the lastwash-tank 14 in the flow direction of the liquid cascade, can beprovided with a drain 66 for discharge of soiled wash liquid for allembodiments in FIGS. 1, 2, 3 and 4.

According to the invention, all conveyor ware washers as per FIGS. 1, 2,3 and 4 are provided with a treatment device 70 for treating of sprayedfinal rinse liquid or for treating a mixture of sprayed final rinseliquid and sprayed post-wash liquid, so that the treated liquid againhas the quality of potable water in microbiological terms.

The treatment device 70 is connected to the final rinse zone 25 as perFIG. 4 and to the final rinse zone 25 and the post-wash zone 46 as perFIGS. 1, 2 and 3, so that it gathers in it the sprayed final rinseliquid or a mixture of the sprayed final rinse liquid and post-washliquid and then returns the treated liquid in the final rinse zone 25for renewed spraying. The treatment device 70 contains preferably amicro-filtration device 72 or ultra filtration device 72 for filtrationof the sprayed final rinse liquid.

As per the preferred embodiments of the invention the micro-filtrationdevice 72 or ultra filtration device 72 contains a transverse flowfilter 74 for micro-filtration or ultra-filtration of the sprayed finalrinse liquid.

As per the special embodiment of the invention the transverse flowfilter 74 contains at least a primary chamber 76 and a secondary chamber78, which are separated from each other by at least one micro-filtrationelement 80 or one ultra-filtration element 80.

The invention can be realized in different embodiments. The treatedpre-used final rinse liquid depending on the embodiment can either beonly sprayed final rinse liquid of the final rinse zone 25 or a mixtureof the sprayed final rinse liquid of the final rinse zone 25 and sprayedpost-wash liquid from the post wash zone 46 or only post-wash liquidfrom the post-wash zone 46 (which is pre-used final rinse liquid usedagain).

The pre-used final rinse liquid to be cleaned flows through the primarychamber 76 with the pressure of a pump from an inlet 82 to an outlet 84,during which a part is filtered through the filtration element 80 andthus reaches in the secondary chamber 78 as cleaned final rinse liquid.This cleaned final rinse liquid can be led back through a discharge pipe86 into the final rinse liquid-supply device 28, for example into thewater heater 30, if from the microbiological perspective it is ofpotable quality.

For cases where the micro-filtration or ultra-filtration for theproduction of water which does not satisfy the quality of potable waterfrom the microbiological perspective, ozone can be added as adisinfecting component to the final rinse liquid which was cleaned bythe filtration for the purpose of disinfecting. For example, anozone-adding device 90 can be provided. This can be connected on the onehand with a connecting pipe 92 to the secondary chamber 78 and on theother hand to the discharge pipe 86.

The treatment device 70 contains a gathering pipe 94, through which itgathers the pre-used final rinse liquid to be cleaned, and supplies itto the inlet 82 of the primary chamber 76 of the transverse flow filter74. The gathering pipe 94 is connected to the post-wash tank 54 in FIGS.1, 2 and 3, in order to gather not only the sprayed final rinse liquidin the final rinse zone 25, but also at least a part of the sprayedpost-wash liquid in the post-wash zone 46. In case of the embodiment ofFIG. 4, the gathering pipe 94 is connected to the floor trough 64, inorder to gather the sprayed final rinse liquid of the final rinse zone25.

The un-cleaned final rinse liquid part flowing through the outlet 84from the primary chamber 76 can be re-used in the dish washing machine.This un-cleaned final rinse liquid can be re-circulated in a circuit asper a preferred embodiment form. There are several embodiments which arepossible.

An embodiment option is shown in FIGS. 1 and 4. The intake pipe 94 isconnected to the inlet 82 of the primary chamber 76 through a finalrinse liquid collection element 100, preferably a collection tank, and aprimary chamber inlet pipe 102, which comprises a supply pump 104feeding into the primary chamber 76. The outlet 84 of the primarychamber 76 is again connected with the final liquid collection element100 through a primary chamber outlet pipe 106. Thus the re-circulatedfinal rinse liquid from the primary chamber 76 mixes with pre-used finalrinse liquid to be cleaned in the final rinse liquid collection element100. The pre-used final rinse liquid flows through the intake pipe 94 inFIG. 4 only from the final rinse zone 25 and additionally in case of theembodiment as per FIG. 1 from the post-wash zone 46 into the final rinseliquid collection element 100. The pump 104 supplies in direction fromthe final rinse liquid collection element 100 to the inlet 82 of theprimary chamber 76. Thus the primary chamber 76, the final rinse liquidcollection element 100 and the pump 104 form a primary chamberre-circulation circuit 108, as is indicated by the arrow 108.

The final rinse liquid collection element 100 can however also bedesigned as a collection element for the collection of soil particles,which can be taken from the collection element 100 continuously orintermittently.

In case of embodiment of FIG. 2 the post-wash tank 54 is connectedthrough the gathering pipe 94 and a pump 104 in the primary chamberinlet pipe 102 to the inlet 82 of the primary chamber 76, without theuse of a final rinse liquid collection element 100. The outlet 84 of theprimary chamber 76 is connected through the primary chamber outlet pipe106 with the post-wash tank 54 in flow connection, in order to lead backthe post-wash liquid from the primary chamber 76 into the post-wash tank54. Thus a primary chamber re-circulation circuit 208 is formed, whichcontains the pump 104 and in its feeding direction one after the otherthe primary chamber 76 of the transverse flow filter 74 and thepost-wash tank 54.

In case of the embodiment of FIG. 3 the suction side of the pump 58 isconnected through the intake pipe 94 with the post-wash tank 54. Thepressure side of the pump 58 is connected through the primary chamberinlet pipe 102 with the inlet 82 of the primary chamber 76. The outlet84 of the primary chamber 76 is connected through the primary chamberoutlet pipe 106 with the final wash liquid supply pipe 56 of thepost-wash nozzles 50 and 52 of the post-wash zone 46. Thus a primarychamber re-circulation circuit 308 is formed, which contains in thesupply direction of the pump 58, consecutively the pump 58, the primarychamber 76, and the post-wash nozzles 50 and 52 and then the post-washtank 54. Here the pump 58 does not only serve the supply of the pre-usedfinal rinse liquid to be cleaned through the primary chamber 76, butalso simultaneously the supply of this final rinse liquid as post-washliquid to the post-wash nozzles 50 and 52. This embodiment requires onepump less than the embodiments as per FIGS. 1 and 2.

In the drawings, parts corresponding to the same function are providedwith the same reference numbers. Features of an embodiment can also becombined with features of the other embodiments and vice versa.

The FIGS. 5, 6 and 7 show different types 190, 290 and 390 of theozone-adding device 90 as examples as per the invention in order tosupply ozone into the filtered final rinse liquid. Arrows 120 and 122show the filtered final rinse liquid and its flow direction before andafter the addition of ozone “O3”.

In case of type 190 of an ozone discharge device 90 from FIG. 5, astorage tank 126 is provided in which ozone “O3” or an ozone air mixturecan penetrate through a gas-permeable membrane 130 into the filteredfinal rinse liquid.

In case of type 290 of an ozone-adding device 90 of FIG. 6 the filteredfinal rinse liquid flows through a tank 226. A venturi-circuit 228 isconnected to the tank 226, in which by a pump 230 filtered final rinseliquid is taken from the tank 226, driven through a venturi element 232and then again supplied into the tank 226. The filtered liquid flowsucks in ozone “O3” or an ozone-air mixture within the venturi element232 and then flows back into the tank 226, where the ozone can mix withthe remaining part of the filtered final rinse liquid.

In case of the type 390 of an ozone adding device 90 in FIG. 7 a venturielement 332 is located in the flow path of the filtered final rinseliquid from the secondary chamber 78 of the transverse flow filter 74 tothe final rinse-supply device 28 for sucking in ozone “O3” or anozone-air mixture from a source of ozone which is schematically shown inthe drawings as “O3”.

1. A conveyor ware washer comprising at least one wash zone for sprayingof wash liquid, at least one final rinse zone for spraying of finalrinse liquid on wares, and a post-wash zone for spraying of post-washliquid on wares between the wash zone and the at least one final rinsezone, a ware conveyor for moving wares through the wash zone, post-washzone and final rinse zone; characterized by a treatment device for thetreatment of sprayed final rinse liquid and sprayed post-wash liquid, sothat the treated liquid is of potable quality of water inmicrobiological terms, whereby the treatment device is made forautomatic gathering of sprayed final rinse liquid and sprayed post-washliquid and for discharge of the treated liquid to the final rinse zonefor renewed spraying as final rinse liquid or at least as a portion offinal rinse liquid.
 2. A conveyor ware washer comprising at least onewash zone for spraying of wash liquid and at least one final rinse zonefor spraying of final rinse liquid on wares; characterized by atreatment device for treatment of sprayed final rinse liquid, so thattreated final rinse liquid is of potable quality of water inmicrobiological terms, whereby the treatment device is made forautomatic gathering of sprayed final rinse liquid and for discharge ofthe treated final rinse liquid to the final rinse zone for renewedspraying as final rinse liquid or at least as part of final rinseliquid.
 3. The conveyor ware washer of claim 2, characterized in thatthe treatment device comprises a micro-filtration device or anultra-filtration device for filtration of the sprayed final rinse liquidof claim
 2. 4. The conveyor ware washer of claim 3, characterized inthat the micro-filtration device or the ultra-filtration devicecomprises a transverse flow filter for providing micro-filtration orultra-filtration.
 5. The conveyor ware washer of claim 4, characterizedin that the transverse flow filter comprises at least one primarychamber and at least one secondary chamber, which are separated fromeach other with at least one micro-filtration element or at least oneultra filtration element, the primary chamber is integrated in a primarychamber liquid circuit by which sprayed liquid to be treated is suppliedto the primary chamber, and the secondary chamber gathers filteredliquid.
 6. The conveyor ware washer of claim 3, characterized in thatthe treatment device comprises an ozone-adding device for feeding ofozone or an ozone-air mixture into the filtered liquid.
 7. The conveyorware washer of claim 2, characterized in that between the wash zone andthe final rinse zone a post-wash zone with post-wash nozzles is locatedfor post washing of wares with post wash liquid in the form of pre-usedfinal rinse liquid, a post-wash tank is provided for gathering finalrinse liquid which was sprayed in the final rinse zone and for gatheringat least a part of post-wash liquid sprayed in the post-wash zone, thatthe treatment device is connected to the post-wash tank in order to taketherefrom a mixture of the sprayed final rinse liquid and of the sprayedpost-wash liquid, for treating it so that it becomes treated final rinseliquid which is of a potable quality of water in microbiological terms.